en Cellular and molecular Neuroscience Cellular and molecular Neuroscience Original Original <p dir="ltr" style="text-align: justify;"><strong>Introduction:</strong> Stimulation of peptidergic fibers activates microglia in the dorsal horn. Microglia&nbsp;activation causes fractalkine (FKN) release, a neuron-glia signal, which enhances pain. The&nbsp;transient vanilloid receptor 1 (TRPV1) mediates the release of neuropeptides, which can&nbsp;subsequently activate glia. TRPV1 and TRPV2 are generally expressed on C and A&delta; fibers,&nbsp;respectively. Expression of both proteins is upregulated during inflammation, but expression of&nbsp;TRPV3 after induction of inflammation is unclear.<br> <strong>Methods:</strong> Adult male Wistar rats were used in all experiments. Arthritis was induced in them&nbsp;by single subcutaneous injection of complete Freund&rsquo;s adjuvant (CFA) in their right hindpaws.&nbsp;Resiniferatoxin (RTX) was used to eliminate peptidergic fibers. We examined the relation&nbsp;between FKN and TRPV3 expression by administration of anti-FKN antibody.<br> <strong>Results: </strong>Our study findings indicated that 1) spinal TRPV3 was mostly expressed on&nbsp;nonpeptidergic fibers, 2) expression of spinal TRPV3 increased following inflammation, 3)&nbsp;elimination of peptidergic fibers decreased spinal TRPV3 expression, 4) alteration of hyperalgesia&nbsp;was compatible with TRPV3 changes in RTX-treated rat, and 5) anti-FKN antibody reduced&nbsp;spinal TRPV3 expression.<br> <strong>Conclusion: </strong>It seems that the hyperalgesia variation during different phases of CFA-induced&nbsp;arthritis correlates with spinal TRPV3 expression variation on peptidergic fibers. Moreover,&nbsp;spinal microglial activation during CFA inflammation is involved in TRPV3 expression changes&nbsp;via FKN signaling.</p> Hyperalgesia, TRPV3, Microglia, Fractalkine 231 240 http://bcn.iums.ac.ir/browse.php?a_code=A-10-787-1&slc_lang=en&sid=1 Sasan Gazerani s_gazerani@hotmail.com 1370031947532846007931 1370031947532846007931 No Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Jalal Zaringhalam jzaringhalam@yahoo.com 1370031947532846007932 1370031947532846007932 Yes Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.Research Center, Shahid Beheshti University of Medical Sciences Homa Manaheji hshardimanaheji@yahoo.com 1370031947532846007933 1370031947532846007933 No Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Sahar Golabi sgolabister@gmail.com 1370031947532846007934 1370031947532846007934 No Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.